The AP Background plugin for WordPress is vulnerable to Cross-Site Request Forgery in all versions up to, and including, 3.8.2. This is due to missing or incorrect nonce validation on the advParallaxBackAdminSaveSlider function. This makes it possible for unauthenticated attackers to create or modify background sliders via a forged request granted they can trick a site administrator into performing an action such as clicking on a link.